It is often desirable to secure an electrical coupling so that the connection cannot be accidentally disconnected, either through human error or otherwise. For example, a critical piece of equipment, such as a heart monitor module, can be connected to a power supply. For many reasons it is desirable to allow the unit to be configured such that it can be disconnected from the power supply without having to break a permanent connection, such as a solder connection. This allows the module to be moved from location to location, as well as to be removed from service for maintenance. In this example, one risk is that a person can accidentally trip over the power cord, disconnecting the unit from the power supply. For obvious reasons, this is to be avoided.
Another application where it is desirable to secure an electrical coupling is in computer and computer-related applications. For example, a computer memory array consists of a number of individual memory modules which are inserted into an array, which comprises a rack supported by a frame. Each memory module is provided with an electrical connector to allow data to be transferred to and from the module, and to provide electrical power to the module. The frame also supports an electrical board (also known as a “plane”), which provides electrical routing to connectors configured to mate with the electrical connectors on the individual modules. The memory array can also comprise support modules such as power supplies, cooling fans, local diagnostic and control modules, etc. These support modules also connect to the plane via connectors. Generally the modules are secured into the rack or the frame by a latch mechanism, preventing the module from becoming disconnected from the plane as a result of incidental impact. However, from time to time a module may need to be removed from the array for service or replacement or the like. In this instance the latch securing the module connector into the plane connector is actuated to allow the module to be removed by an operator. The risk is that the operator can accidentally remove the wrong module.
As an example, consider FIG. 1 which depicts an oblique view of a computer system 2 which includes a memory array device “A” which is connected to a main controller “C” by cable 4. The memory array “A” includes an enclosure 12 which fits over a frame (not shown). The frame supports a variety of modules which electrically connect to a plane (also not shown) by electrical connectors. The modules can include memory modules 5, 6, 7 and support modules 8, 9, 10 and 11. The support modules can include local controllers, power supplies, and cooling units. Each memory module is secured into the frame by a latch 14. The controller “C” can be connected to other memory arrays similar to the device “A”, and can also be provided with a user display 20.
One function which can be performed either by a local controller within the memory array “A” or by the main controller “C” is a routine diagnostic program. The diagnostic program can detect errors or malfunctions within individual modules in the array “A”. When a module is detected which may need to be serviced or replaced, the user can be notified through the user display 20. As part of the diagnostic program, the controller “C” (or a local controller) can electronically remove the module from service, either automatically or as authorized by a user. Electronically removing the module from service typically encompasses identifying a redundant module to perform the capabilities of the module to be serviced, and identifying to the system that the defective module should no longer be used to perform its normal functions. Electronically removing the module from service can also include depriving the module of electrical power so that when the electrical connections between the module and the plane are decoupled, arcing between the contacts does not occur. Once the defective module has been electronically removed from service, it can be physically removed by an operator.
At this point, the operator ideally removes the module from the array so that the module can be serviced or replaced. However, it is possible that the operator can accidentally remove the wrong module. This is not an unlikely event in a large array system which can have hundreds of memory arrays, each memory array having tens of modules. The consequences can be significant. For example, if an in-service power module or a local control module is disconnected from an array, it is possible that all data stored by the array can be lost. While typically each module in an array has a redundant back-up module, if the active module is accidentally removed (versus the defective back-up module), then the whole array can be affected.
As another example, typically memory modules are actively backed-up using a dedicated module to back up two or more primary modules. For example, with respect to FIG. 1, a “data stripe” S1 can consist of two primary memory modules 5 and 6, and a back-up module 7. A single back-up module 7, when used in conjunction with a back-up algorithm and a computer processor, can be used to back-up the contents of two primary modules 5 and 6. For example, the back-up module 7 can store the binary sum of the modules 5 and 6. In this way, if memory is lost from module 5, it can be restored merely by processing the contents of modules 6 and 7 using the back-up algorithm to calculate the lost data in module 5. However, if an operator were to accidentally remove one of these modules from service before it has been operationally removed from service by the array controller, then any data lost in the two remaining modules cannot be restored, and the data can be irretrievably lost.
The system can be further complicated by advances in memory arrays, for example where the back-up module is selected by a controller, rather than being the third module in a memory stripe. In this instance, the back-up module can be one of any of the modules in the array. Additionally, in some configurations the memory stripe consists of five memory modules, and so it is not always obvious that the third module down is the back-up module. These advanced systems make it difficult for an on-site operator to know which modules are active, and which modules are performing what functions. As a result, it is often necessary to bring in an off-site technician with special knowledge of the system to remove the defective module. This of course results in delays in getting the defective module serviced, and increases the cost to the user of having the module serviced.
Further complicating the situation is the fact that the user may move modules from location to location within the array, so that the resulting configuration does not correspond to the original configuration. For example, the original configuration can identify module “X” as being associated with slot “Y” in the array. The module is thus tagged with an identifier visible to the user, identifying the module as “module X”. Further, the diagnostic program can be configured to identify a module by its location within the array. Thus, if the diagnostic program determines that the module in slot “Y” is defective, and the configuration indicates that module “X” is in slot “Y”, the program will notify the user that “module ‘X’ needs to be removed for service”. The user will then locate the module which is tagged “module X”, and will remove it from service. However, if module “X” has been moved to a new location, the user can end up removing the wrong module.
One solution is to provide an indicator on the module, or next to the module, such as a light emitting diode (LED), which illuminates when the module has been operationally removed from service. This indicates that the module can now be physically removed from the array. However, there is still nothing in this configuration which actually prevents the operator from removing a module from the array before it has been removed from service.
The examples given above are only a small sampling of the overall problem regarding accidental disconnecting of electronic and electrical couplings. The problem not only applies to power connections and modules in computer arrays, to any situation where an electronic/electrical coupling which can be accidentally decoupled is to be avoided. Further, the problem can also apply to any kind of connection where accidental or premature decoupling of connectors is to be avoided, including hydraulic and pneumatic systems. What is needed then is a way to prevent the accidental decoupling of connectors, and in particular electrical and electronic connections.